| Title of Invention | ROTARY ELECTRIC MACHINE |
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| Abstract | A rotary electric machine includes a rotor, a field magnet formed from a magnet, and a yoke surrounding the field magnet. An armature core forming the rotor is formed from a laminated iron core formed by laminating plural core plates and both of the core plates provided at both ends of the armature core have press shearing parts of arm parts forming slots of the core plate, and the press shearing parts are press-chamfered on either the press shearing part burr side or the press shearing part shear droop side. |
| Full Text | ROTARY ELECTRIC MACHINE BACKGROUND OF THE INVENTION Field of the Invention This invention relktiefe to a structure of a. rotary electric machine, and more particularly, to a structure of an armature core thereof. Description of the Related Art One of conventional devices relating to a core of a rotary electric machine is disclosed in JP-B-2802862. The device of JP-B-2802862 is configured to form chamfered edges in respective arm of the uppermost and the lowest core plates among core plates, which forms a core, adjacent to respective slots in order to suppress burrs or the like, which are caused by punching on upper and lower surfaces of the core, for the purpose of reducing the thickness of a powder coating and preventing an accident due to a short circuit of a winding. Such a device, depending on a structure of a metal die, is designed to chamfer the upper and lower surfaces of the core, namely, to press-chamfer both of a burr side and a shear droop side. In the method of manufacturing a core in accordance with JP-B-2802862, it is required to form chamfered edges on the both of an upper surface side and a lower surface side of a punched core plate. This causes problems that a structure of a metal die is complicated, the productivity is deteriorated, and a cost of a metal die increases. Further, both of a burr side and a ^hear droop side, which are the upper and lower surfaces of the core, are chamfered, so that the contours of chamfered edges are not same. This causes the thickness and the strength of a layer of a powder coating of the chamfered edge to be uneven between the upper and lower surfaces of the core, and thereby the quality and the productivity of the powder coating and a coil winding to be deteriorated. SUMMARY OF THE INVENTION The present invention is to solve the above problems, and therefore aims at providing a rotary electric machine comprising: a rotor having an armature core ; a field magnet; and a yoke surrounding the field magnet, wherein an armature core is formed from laminated iron cores, each of which is formed with plural core plates and both of the core plates located at the both ends of the armature core have press shearing parts of arm parts forming slots of the core plate, the press shearing parts of which are press-chamfered on either the press shearing part burr side or the press shearing part shear droop side. In accordance with the invention, a core plate with one surface chamfered is placed at one end of each laminated iron core formed from plural core plates, and the laminated iron cores are assembled in such a way that the core plates having been chamfered are located at the both ends of an armature core. Accordingly, a press metal die used in core processing can be simplified in structure, the productivity of the metal die is improved, cost of the metal die can be suppressed, and a rotary electric machine of low cost can be obtained. Moreover, in accordance with the invention, the core plate with a chamfered edge is put at only one end of each laminated ""iron core formed from plural core plates, and the plural laminated iron cores are coupled into an armature core in such a way that the core plate with the chamfered edges are arranged at both ends of the armature core, resulting in the same size in the chamfered edges at the both ends of the armature core. This allows the thickness of a film to be evened at the both ends in reducing the thickness of a powder coating to be I even at the both ends even if the thickness of a powder coating is thin, so that the quality and the productivity of the powder co-ating and the coil winding can be improved. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view of a rotary electric machine in accordance with the invention. Fig. 2 is a plan view of a core plate of a rotary electric 1 machine in accordance with the invention. Figs. 3A and 3B illustrate a core plate at one end of a laminated iron core in adcordance with the invention, in which Fig. 3A is a plan view, and Fig. 3B is an enlarged view of an arm part of the above. Fig. 4 is a sectional view of a chamfering on a burr side of a press shearing part of a core plate of a rotary electric machine in accordance with a first embodiment of the invention. Fig. 5 is a sectional view of a chamfering on a burr side of a press shearing part of a core plate of a rotary electric machine in accordance with a first embodiment of the invention. Fig. 6 is a sectional view of a laminated iron core of a rotary electric machine in accordance with the invention. Fig. 7 is a front view of an armature core of a rotary electric machine in accordance with the invention. Figs. 8A and 8B illustrate a powder-coated armature core of a rotary electric machine in accordance with the invention, in which Fig. 8A is a plan view of the above, and Fig. 8B is a sectional view of an arm part of the above. Figs. 9A to 9D illustrate an armature core of a rotary electric machine in accordance with a second embodiment of the invention, in which Fig. 9A is a front view of the above, and Figs. 9B, 9C and 9D are sectional views of the above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now, a description will be given of embodiments of the present invention with reference to the accompanying drawings. Embodiment 1 Fig. 1 is a sectional view of a rotary electric machine 1 with a brush. A yoke 10 is in the shape of a cylinder having a bottom. A magnet 11 is fixed to an inner circumference of a yoke circular tube 10a through a holder 12 by pressure insertion and such. An armature 20 is provided at a predetermined gap between the armature 20 and an inner circumferential surface of the magnet 11, which forms a field magnet. The armature 20 is fixed to a shaft 21 and has a coil winding 24 on an armature core 23 coated with a powder coating. The armature 20 is freely rotatably supported on a bearing 13 held on a bearing case 10b formed in the yoke 10 and a bearing 31 held on a bearing case 30a provided in a housing 30. Fig. 2 illustrates the shape of a core plate in a plan view. A core plate 25 has a slot 25a on which the winding coil 24 is wound, an arm 25b, and a shoe-shaped part 25c. The core plate 25 is formed by punching by means of a press machine. Fig. 3A illustrates the shape of a core plate 26 in a plan view, which is placed at one end of each laminated iron core in forming the iron core with the core plates 25. The core plate 26 is same in planar shape and in thickness as the core plate 25, except for a chamfered edge mentioned later. The core plate 26 at one end of the laminated iron core has a slot 26a on which the winding coil 24 is wound, an arm 26b, and a shoe-shaped part 2 6c. The core plate 2 6, however, has a chamfered edge 26d, which is formed on a press shearing part of the arm 26b adjacent to the slot 2 6a when punched out by means of a press machine, as shown in an enlarged view of Fig. 3B. The armature core 23 is formed by assembling plural blocks of laminated iron cores. Fig. 6 illustrates the shape of a laminated iron core 28, which forms one block, in a sectional view. The plural core plates 25 and one core plate 26 are laminated via concave-convex fitting 28a to form the laminated iron core 28. The core plate 26 provided with the chamfered edge 26d is placed at one end of the laminated iron core 28 so that the chamfered edge 26d would be on an outer side. The laminated iron core 28 has, at the center thereof, a shaft fitting hole 32 into which the shaft 21 is fitted. Fig. 7 illustrates a shape of an armature core. The armature core 23 consists of the plural blocks of laminated iron cores 28 combined in parallel in an axial direction. At the both ends of the armature core 23, the core plates 26 having the chamfered edges 26d are located in parallel. Fig. 7 illustrates the armature core 23 combined with three laminated iron cores 28, but the number of the laminated iron core 28 is not limited so long as the armature core 23 consists of plural laminated iron cores 28 and the core plates 26 having the chamfered edges 2 6d are located at the both ends 23a. As the chamfered edge 2 6d is formed on the same side of each core plate " by means of a press machine, all the contours of the chamfered edges on the core plates 26 placed at the both ends 23a of the armature core 23 are approximately same. In forming the core plate 26, a material steel plate is punched by means of a pressing die, and then, any one of a burr side and a shear droop side of the punched steel plate is surface-struck by means of a press machine to form the chamfered edge 26d. Fig. 4 is a sectional view of an arm part, which is chamfered on a burr side 27a of the press shearing part. As the press-chamfered edge 26d is formed only on the press shearing burr side 27a of the arm 26b, uniform contour of a press-chamfered shape can always be*obtained. Accordingly, a layer of a power coating of the laminated iron core 28, which is provided on one end thereof with the core plates 26 having chamfered edges on the same side, can be reduced in thickness. Fig. 5 is a sectional view of an arm, which is chamfered on a shear droop side 27b of the press shearing part. As the press-chamfered edge 26d is formed only on the press shearing droop side 27b of the arm 26b, uniform contour of a press-chamfered shape can always be obtained, similarly to the case of the burr side. As the armature core 23 is arranged as described above in Embodiment 1, the chamfered edge 26d, which is formed on the core plate 26 at one end of each laminated iron core 28 consisting of plural core plates, exists only on one side, that is, either the burr sid6 or the shear droop side, which simplifies the structure of a pressing die, improve the productivity, and reduces the cost of a die. Further, the chamfered edge 26d is formed only on the core plate 26 at one end of each laminated iron core 28 consisting of plural core plates, and the plural laminated iron cores 28 are so arranged that the core plates having chamfered edges would be at the both ends 23a of the armature core 23. Accordingly, the both ends 23a of the armature core 23 are either the burr side chamfering part 2Ja or the shear droop side chamfering part 27b of the core plates punched out by a press machine. This enables the amount of chamfering at the both ends 23a of the armature core 23 to be equal, so that the thickness of the powder coating 22 can be made equal at the both end surfaces 23a even if a layer of the powder coating 22 is thin. This contributes to imprdvements in quality and productivity of the powder coating 22 and the coil winding 24. In chamfering the burr side 27b, compared with chamfering the shear droop side 27a, a ptocessing ratio of a pressing is smaller, and thereby, magnetic strain can be reduced. This leads to an effect of improving motor efficiency due to reduction of iron loss. Embodiment 2 In Embodiment 2, the laminated iron cores 28 are rotated by 360/N degrees when the armaturd core 23 is assembled with N pieces of laminated iron cores 28 in parallel in an axial direction. That is to say, the' plural laminated iron cores 28 are equally rotated by the same angle to be combined each other in parallel in the axial direction. The other structure is the same as that in Embodiment 1. Fig. 9A illustrates an image of an arrangement of the laminated iron cores. Figs. 9B, 9C, and 9D are sectional views of the laminated iron core along lines b-b, c-c, and d-d, respectively. The core plate 25 and the core plate 26 at one end of the laminated iron core have positioning marks 28b used in combining the laminated iron cores 28 in parallel in the axial direction. The laminated iron cores 28 are rotated by 360/N degrees (120 degrees, for example) with the positioning mark 28b which is used as a standard in providing N pieces (three, for example) of laminated iron cores 28 in parallel. According to Embodiment 2, the rotary electric machine has such a structure described above that the anisotropy of the core plate 25 can be canceled, in addition to the effect of Embodiment 1. This reduces torque loss and cogging torque. Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this is not limited to the illustrative embodiments set fortji herein. What is Claimed is: 1. A rotary electric machine comprising: a rotor having an armature core; a field magnet formed from a magnet; and a yoke surrounding the field magnet, wherein the armature core is formed from a laminated iron core consisting of plural core plates and both of the core plates placed at the both ends of the armature core have press shearing parts of arms forming slots of the core plate, the press shearing parts of which are press-chamfered on either the press shearing part burr side or the press shearing part shear droop side. 2. The rotary electric machine according to Claim 1, wherein the armature core is constructed with plural blocks laminated iron cores arranged in parallel in an axial direction. 3. The rotary electric machine according to Claim 2, wherein the plural blocks of laminated iron cores are combined in parallel in the axial direction equally rotated around the axis by a same angle, respectively. |
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| Patent Number | 279675 | ||||||||||||
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| Indian Patent Application Number | 114/CHE/2010 | ||||||||||||
| PG Journal Number | 05/2017 | ||||||||||||
| Publication Date | 03-Feb-2017 | ||||||||||||
| Grant Date | 28-Jan-2017 | ||||||||||||
| Date of Filing | 18-Jan-2010 | ||||||||||||
| Name of Patentee | MITSUBISHI ELECTRIC CORPORATION | ||||||||||||
| Applicant Address | 7-3 MARUNOUCHI 2- CHOME, CHIYODA-KU, TOKYO 100-8310. | ||||||||||||
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| PCT International Classification Number | H02K 15/02 | ||||||||||||
| PCT International Application Number | N/A | ||||||||||||
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